Abstract: Solar power systems and methods utilize DC power transmission and centralized power inversion. The solar power systems include a photovoltaic (PV) bus system and a fixed bus system. The PV system utilizes a control mode handoff control method, which includes determining that a local maximum power point tracking (MPPT) control is enabled; in response to determining that the local MPPT control is enabled, starting an MPPT mode timer; performing local MPPT; determining that the MPPT mode timer is greater than a predetermined period; and, in response to determining that the MPPT mode timer is greater than a predetermined period, handing off MPPT control to the next MPPT controller. The distributed MPPT control method may include sequential MPPT control, adaptive ?V MPPT control, and/or power limiting control. The fixed bus system includes PV string-level MPPT controllers and a fixed DC input central inverter or multiple fixed DC modular inverters.

Abstract: Methods, apparatus, systems and articles of manufacture are disclosed to transmit signal in isolated gate drivers. An example apparatus includes a first encoder including: an edge detector coupled to a first sensor; a first clock counter coupled to the edge detector; a first signal selector coupled to the first clock counter; and a first multiplexer including coupled to a signal generator, the first clock counter, and the first signal selector; and a second encoder including: a level detector coupled to a second sensor; a second clock counter coupled to the level detector; a second signal selector coupled to the level detector and the second clock counter; and a second multiplexer coupled to the first multiplexer, a reference voltage, the second signal selector, and a modulator.

Abstract: A solid state power controller for delivering power to a load is provided. The solid state power controller includes a set of sections, where each section includes at least one power switching block. The solid state power controller further includes protection circuitry in each section. The protection circuitry is configured to prevent a fault occurring in one power switching block to propagate to the other sections, to other power switching blocks, or to the load.

Abstract: In-chip decoupling capacitor circuits refer to decoupling capacitors (DCAPs) that are placed on a chip. These DCAPs are generally used to manage power supply noise for the chip, and can be utilized individually or as a distributed system. In some cases, DCAPs may make up a significant portion of the chip. Unfortunately, defects in DCAPs will degrade over time, will encroach into active logic, and will further cause automatic test pattern generation (ATPG) failure. To date, there has been a lack of structural test coverage for DCAP circuits, which reduces test coverage of the chip as a whole. To this end, defects on the chip as they relate to DCAPs (i.e. shorts in the DCAP) may not be detected. The present disclosure provides a structural test system and method for DCAPs and other passive logic components located on-chip.

Abstract: This power supply device includes: a power interconnection path connecting a power interconnection port to a power conversion unit via a first switch; a stand-alone power supply path leading from an auxiliary input port via a second switch to an output port to which a load is connected; a storage-battery-side power supply path leading from a storage battery via the power conversion unit to the output port; and a control unit, the control unit causing the power conversion unit to charge/discharge the storage battery when interconnected with a commercial power grid, the control unit supplying power to the load via one of the stand-alone power supply path and the storage-battery-side power supply path when disconnected from the commercial power grid, the control unit switching the power supply path from the one to the other within an extremely short time period such as not to influence the load.

Abstract: A ferroresonant transformer assembly, which is adapted to be connected to a primary power source, an inverter system, a resonant capacitor, and at least one load, comprises a core, a main shunt, and first, second, and third windings. The main shunt is arranged to define a primary side and a secondary side of the ferroresonant transformer. The first windings are arranged on the primary side of the ferroresonant transformer and are configured to be operatively connected to the primary power source. The second windings are arranged on the secondary side of the ferroresonant transformer and are configured to be operatively connected to the inverter system. The third windings arranged on the secondary side of the ferroresonant transformer and are configured to be selectively operatively connected to or disconnected from the resonant capacitor.

Abstract: A system and method is directed to charging and discharging an energy-tank capacitor of a power supply unit (PSU) in a computing system. The PSU has a forward converter, a buck converter, a switch box, and an option box. The forward converter has a transformer. A primary winding of the transformer is coupled to an input of the PSU, while a secondary winding of the transformer is coupled to an output of the PSU. Two or more components of the forward converter are shared with the buck converter to support the functionality of the buck converter when it is enabled. The switch box has a power switch and a controller switch connected to the forward converter. The energy stored on the energy-tank capacitor is capable of supporting power consumption of the server system during a hold-up time, when an input power to the PSU is interrupted.

Abstract: A method of thermal mitigation in a device having a plurality of non-real-time processing units (PUs) and a plurality of real-time PUs, including connecting each of the plurality of real-time PUs and the plurality of non-real-time PUs to a first power supply, and performing thermal mitigation. Performing thermal mitigation includes disconnecting each of the plurality of non-real-time PUs except one of the plurality of non-real-time PUs from the first power supply resulting in an active non-real-time PU, and connecting a second power supply that derives power from the first power supply to the active non-real-time PU, wherein a voltage supplied by the second power supply is less than a voltage supplied by the first power supply.

Abstract: A failure tolerant capacitor device comprises a plurality of capacitor elements connected in parallel. For each capacitor element, there is a detection element and a connection element. The detection element is adapted for detecting a capacitor voltage across the capacitor element falling below a predefined voltage threshold and/or for detecting a capacitor current through the capacitor element raising above a predefined current threshold and for turning off the connection element when the capacitor voltage is below the predefined voltage threshold and/or the capacitor current is above the predefined current threshold. The connection element is adapted for disconnecting the capacitor element from other ones of the plurality of parallel connected capacitor elements when turned off. The detection element and the connection element each include a transistor.

Abstract: A heat pump device includes an inverter control unit for controlling an inverter. The inverter control unit includes a constraint-energization control unit that, during operation standby of a compressor, determines whether heating to the compressor is necessary, on the basis of a refrigeration stagnation amount in the compressor, and, when having determined that heating to the compressor is necessary, selects, according to the refrigeration stagnation amount, any one of direct-current energization for supplying a direct-current voltage to the motor and high-frequency energization for supplying a high-frequency voltage having a frequency higher than a frequency during a normal operation to the motor, so as to output a constraint energization command for carrying out constraint energization of the motor; and a driving-signal generating unit that generates a driving signal on the basis of the constraint energization command.

Abstract: A wireless power transmitter includes a wireless power controller configured to receive an alternating current (AC) voltage, to convert the AC voltage into a direct current (DC) voltage, and to generate an induced current from the DC voltage according to a switching control for a transformer; and a resonator configured to be resonated by the induced current to wirelessly output charging power.

Abstract: A sensor circuit and method. The circuit includes a first subcircuit that includes a first sense capacitor, a first integration capacitor, and a first clock input for receiving a first digital clock signal for initiating discharge of the first integration capacitor at time T. The circuit includes a second subcircuit that includes a second sense capacitor, a second integration capacitor, and a second clock input for receiving a second digital clock signal for initiating discharge of the second integration capacitor at time T+Td. A rate of discharge of the first and second integration capacitors is at least partly determined by a capacitance of the first and second sense capacitor, respectively. At time Teval, after initiation of discharge of the first and second sense capacitors, the extent to which the first and second integration capacitors have discharged is compared. A digital signal indicating the result of the comparison is outputted.

Abstract: For optimizing a chronological development of consumption of electric power by a group of different consumers with regard to a supply of electric power including electric power from at least one wind or solar power generator, characteristic time curves of the consumption of electric power are determined at a high temporal resolution. A prognosis is made of a chronological development of the supply of electric power from the at least one power generator for a future period of time, and a plan for apportioning electric power to the individual consumers within the future period of time is made based on the characteristic time curves of the consumption of electric power by the individual consumers, the prognosis, and user goal setting by a user of the consumers resulting in different weightings of consumption of electric power by different consumers and supply of electric power by different power sources.

Abstract: A system and methods providing for minimizing the arc energy delivered to the pads of a plurality of contactors using a single control coil based on monitoring the electrical sine waves of the three alternating current electrical poles and calculating the instant to energize or deenergize a single control coil. The remainder of the contactors will make or break based on an offset in time from the making or breaking of the control contactor.

Abstract: A central site, using grid operator requirements to reduce portfolio power according to frequency decreases within a frequency band, determines the optimal frequency triggers at which each load within a portfolio should reduce power and by how much power. Power availability of each load is optimized. These triggers and individual load power reductions are periodically dispatched from the central site to the individual loads. Each load detects when a frequency deviation occurs and is able to independently and rapidly reduce its power consumption according to the triggers and corresponding power reductions it received previous to the frequency deviation. Reliance upon the central site to detect a frequency deviation and then to dispatch power reductions in real time is not needed. The system also detects frequency increases and directs a portfolio of loads to consume more power. The system applies to energy loads and detection of a grid signal in general.

Abstract: Methods, systems, and computer readable media for adaptive out of step protection for power generators with load resynchronization capability are disclosed. According to one method, when a fault condition occurs in a load being supplied by a power generator, a number of pole slips expected to occur in the generator due to the fault before resynchronization is estimated. It is determined whether the estimated number of pole slips exceeds a threshold. An offline or online status of the generator is controlled based on the determination as to whether the estimated number of pole slips exceeds the threshold.

Abstract: A safety shut-off system and method are provided for eliminating power to a load in the event of smoke detection. The system may comprise a device located at the appliance for detecting a signal from a smoke detector, and cutting power to the appliance only when the appliance is in use. The device may be synchronized with any standard smoke alarm signal to reduce the number of false positive shut-offs. The system may also comprise a smoke alarm hard-wired to a circuit breaker, for shutting off power to all appliances on a particular breaker upon receipt of a signal from the smoke alarm, and only when the appliances on the breaker are in use. The system may also have the ability to shut off one breaker, multiple breakers, or all breakers at different time increments to actively prevent and reduce the damages caused by fires.

Abstract: A router module is arranged in a housing of a smart television. The router module is externally connected to a modem for surfing the Internet. The router module is electrically connected to a micro processing unit of the smart television. Therefore, the smart television is connected to the Internet through the router module. A wireless transmission chip of the router module is configured to process Internet signals. An antenna module is configured to wirelessly transmit the Internet signals, so that wireless network is shared to outside.

Abstract: A line voltage device with an auxiliary power connection for a bathing installation. An exemplary embodiment of the device includes a housing structure, and a primary electrical power connection connected to the housing structure and including a primary wiring cable for connection to a line voltage source. A load system is disposed within or adjacent the housing and configured for powered operation by electrical power from the primary electrical power connection. An auxiliary power connection is provided for electrical connection to a separate bathing installation device to provide power to the separate device. A wiring circuit is disposed within or adjacent the housing structure and electrically couples the primary electrical power connection and the auxiliary power connection so that line voltage power is shared between the load system and the separate bathing installation device.

Abstract: A resonance frequency adjusting circuit in electronic communication with a power supply and a load connected to the power supply includes a first LC filter, a capacitor, a switch, and a frequency detecting and control module. The first LC filter circuit is electrically connected between the power supply and the load. The switch is electrically connected between the capacitor and ground. The frequency detecting and control module detects a current transient frequency of the load, compares the current transient frequency with a first resonance frequency of the first LC filter circuit, and controls the switch to turn on/off according to the comparison.

Abstract: A line frequency monitoring and load shedding control apparatus is placed in or closely coupled to a power load and monitors the line frequency of the alternating current electric power source supplying the power load. When a decrease in line frequency is detected, this line frequency monitoring and load shedding control apparatus may interrupt certain portions of the power load, thereby allowing the power source frequency to stabilize. Subsequently, the line frequency monitoring and load shedding control apparatus makes a determination to return operation of the load that was shed to a normal state of operation as the power line frequency recovers to a normal operating frequency. Fixed time delays, e.g., adjustable, programmable, etc., and/or pseudo random time delays may be incorporated to sequentially reconnect the loads back onto the power source, thereby preventing the loads previously shed from being reconnected all at the same time.

Abstract: Processes, machines, and articles of manufacture that may serve to enable the detection or determination of alternating line voltages from an alternating power source, such as the power grid, are provided. This automatic sensing may be useful when connections are made to the power grid, such that when connections are made, the connections may be configured to be compatible with the available power source. This automatic sensing may also be useful if power sources change characteristics over time or if devices may be connected to different power sources over time.

Abstract: There is provided an apparatus for the anti-islanding of a power conditioning system. The apparatus for the anti-islanding of a power conditioning system according to the present invention is applied to a power conditioning system including a DC/DC converter and a DC/AC inverter in order to transfer power from a solar cell array to a grid. The apparatus for the anti-islanding of a power conditioning system may include an injection signal generator generating an injection signal, an adder generating a final fundamental wave command value, a main controller performing the power control according to the final fundamental wave command value and stopping the operation of the power conditioning system when the level of the detected injection signal has reached the predetermined reference level or more, and an injection signal detector detecting the injection signal included in voltage and providing them to the main controller.

Abstract: A method of inducing a high efficiency conductive state at room temperature within a conductive mass (1) by injecting a complex modulated carrier signal (7) into one or more injection points (2,3) whereby the carrier signal and the subharmonic modulation frequencies (4,5,6) which are imbedded in the modulation of the carrier signal are tuned to the mass lattice qualities of the material. The amplitude and phase relationship of each individual subharmonic frequencies (4,5,6) are respectively tuned to the mass lattice qualities of the conductive mass (1). This method of excitation, with precise matching of subharmonic modulation frequencies, and with a precise matching concordant harmonic of the carrier frequency, creates an observed ionic excitation throughout the conductive mass (1) at room temperature.

Abstract: A method of controlling a plurality of output voltages in a multi-output power supply device for generating a plurality of output powers by using a transformer. The method includes, if a system to which power is supplied from the multi-output power supply device is in a standby mode, blocking any one of at least two output powers of a secondary side of the transformer, wherein the blocked power is supplied to the system; and compensating for a resistance of a feedback circuit connected to a switching controller of a power switch of a primary side of the transformer in relation to one or more unblocked output powers of the transformer and maintaining the output of the unblocked output power to be constant.

Abstract: A modification method and system. The method includes detecting and monitoring by a computing system, a frequency signal associated with an input voltage signal used for powering a plurality of power consumption devices at a specified location. The computing system compares the frequency signal to a predetermined frequency value. The computing system determines that the frequency signal comprises a first value that is not equal to the predetermined frequency value. The computing system calculates a difference value between the first value and the predetermined frequency value. The computing system compares the difference value to a second value. The computing system enables a load adjustment modification process associated with the plurality of power consumption devices. The computing system generates and stores a report associated with the load adjustment modification process.

Abstract: A load management method and system. The method includes detecting and monitoring by a computing system, a frequency signal associated with an input voltage signal used for powering computing apparatuses at a specified location. The computing system compares the frequency signal to a predetermined frequency value. The computing system determines that the frequency signal comprises a first value that is not equal to the predetermined frequency value. The computing system calculates a difference value between the first value and the predetermined frequency value. The computing system compares the difference value to a second value and analyzes a power demand profile. The computing system enables a load adjustment modification process associated with the plurality of power consumption devices based on the difference value and the power demand profile. The computing system generates and stores a report associated with the load adjustment modification process.

Abstract: A modification method and system. The method includes detecting and monitoring by a computing system, a frequency signal associated with an input voltage signal used for powering a plurality of power consumption devices at a specified location. The computing system compares the frequency signal to a predetermined frequency value. The computing system determines that the frequency signal comprises a first value that is not equal to the predetermined frequency value. The computing system calculates a difference value between the first value and the predetermined frequency value. The computing system compares the difference value to a second value. The computing system enables a load adjustment modification process associated with the plurality of power consumption devices. The computing system generates and stores a report associated with the load adjustment modification process.

Abstract: A load management method and system. The method includes detecting and monitoring by a computing system, a frequency signal associated with an input voltage signal used for powering computing apparatuses at a specified location. The computing system compares the frequency signal to a predetermined frequency value. The computing system determines that the frequency signal comprises a first value that is not equal to the predetermined frequency value. The computing system calculates a difference value between the first value and the predetermined frequency value. The computing system compares the difference value to a second value and analyzes a power demand profile. The computing system enables a load adjustment modification process associated with the plurality of power consumption devices based on the difference value and the power demand profile. The computing system generates and stores a report associated with the load adjustment modification process.

Abstract: A method is provided for using a temporary power source to transfer a power bus from a first power source to a second power source. The first power source operates at a first electrical frequency, and the second power source operates at a second electrical frequency that is different from the first electrical frequency. The method includes adjusting the output frequency of the temporary power source to match the first electrical frequency and supplying power to the power bus from the temporary power source. The method also includes disconnecting the first power source from the power bus. The method further includes adjusting the output frequency of the temporary power source to match the second electrical frequency. The method further includes coupling the second power source to the power bus.

Abstract: A circuit for a fill-level measuring device is for the fast switching-on of a high-frequency element on a ground port is disclosed. The circuit comprises a switching unit with a circuit mass; a high-frequency element with a high-frequency mass; and a coupling element that couples the two masses together and at the same time insulates them from each other in a direct-current manner. In this way the switching unit can be arranged on the GND port of the HF-element, without influencing the HF characteristics of said HF element.

Abstract: A power converter having an aircraft power source detector configured to limit the amount of power that can be drawn by the power converter when utilized in an aircraft. The power converter may detect an artifact of the aircraft power source, such as the 400 Hz ripple noise on an aircraft power line, or existing in the aircraft cabin, such EMI or aircraft lighting.

Abstract: A multi-output power supply device includes a first power switch, a first switch controller that controls the first power switch, a transformer that transforms a power supplied from the first power switch, first through Nth output circuits connected to a secondary side of the transformer, where N is a positive integer greater than 1, a second power switch that switches the power output from one of the first through Nth output circuits, a second switch controller that controls the second power switch, a feedback circuit that feeds back output voltages of the first through Nth output circuits, and a feedback compensation circuit that performs a switching operation complementarily with the second power switch to compensate for a resistance of the feedback circuit. Accordingly, when power output to one of the output circuits is blocked, the multi-output power supply device can stably control the power output to the other output circuits.

Abstract: A power pick-up for an Inductively Coupled Power Transfer (ICPT) system is provided having a resonant pick up circuit. The natural frequency of the pick-up circuit may be varied by controlling the conductance or capacitance of a variable reactive in the resonant circuit. The load being supplied by the pick-up circuit is sensed, and the effective capacitance or inductance of the variable reactive component is controlled to vary the natural resonant frequency of the pick-up circuit to thereby control the power flow into the pick-up to satisfy the power required by the load.

Abstract: An object is to provide a duplex power supply for auxiliary machines. A power supply device includes a switching section that is connected to a direct-current link between a generator-side inverter and a grid-side inverter via an auxiliary machine power inverter for converting direct-current power supplied from the direct-current link into alternating-current power to form a first path, that is connected somewhere between a power-converting section and a utility grid to form a second path, and that is connected to auxiliary machines to form a third path, and the switching section switches between connection of the third path to the first path and connection of the third path to the second path.

Abstract: A circuit breaker includes a line terminal, a load terminal, separable contacts electrically connected in series between the terminals, a neutral conductor, and an operating mechanism structured to open and close the contacts and trip open the contacts in response to a trip signal. A first sensor senses an electrical characteristic operatively associated with the contacts. A second sensor detects zero crossings, a consecutive pair of the crossings defining a corresponding half-cycle and a first frequency. A processor cooperates with the sensors and includes a routine and a timer having a second frequency. The routine determines, for each of the half-cycles and responsive to the timer, plural samples of the sensed electrical characteristic in a phase synchronized relationship to a corresponding one of the crossings, and determines whether one of the frequencies exceeds a number of corresponding predetermined values for a number of times and responsively outputs the trip signal.

Abstract: Apparatus, systems, and methods for powering an electric device coupled to a patient to reduce transients on patient monitoring devices are provided herein. In some embodiments, an apparatus for reducing transient electrical events on a patient monitoring device may include a device that can be powered on or off to cause current flow through a load of the device and which has a line out that is capacitively coupled to a patient during use; and a control circuit to control a periodic coupling of first and second voltage sources to the load out of phase at a predetermined carrier frequency to provide continuous current flow through the load in alternating directions, and to control the periodic coupling of first and second voltage sources to the load in phase at a predetermined carrier frequency to provide no current flow through the load.

Abstract: A vacuum electronic switch detection system allows multiple user selectable vacuum modes to be chosen with only one micro-controller input available for performing the multiple selectable modes. The switch detection system provides multiple voltage ratio control signals indicative of multiple switch position possibilities.

Abstract: An induction motor control device includes an inverter circuit for driving an induction motor by outputting a command voltage, a current detector for detecting an output current, a magnetic flux estimation observer for generating an estimated magnetic flux, an estimated current, and a phase command for the motor using the command voltage and the output current, a primary angular speed estimator for estimating a primary angular speed using the estimated magnetic flux, a slip compensator for calculating a slip angular frequency using the output current, a first angular speed estimator for estimating a first angular speed using the primary angular speed and the output current, a second angular speed estimator for estimating a second angular speed using the output current, the estimated magnetic flux, and the estimated current, and a resistance estimator for estimating a secondary resistance value of the motor using the first and second angular speeds.

Abstract: A coloring apparatus 1 includes a coloring nozzle 31 for spouting a coloring material, a signal generator 53, and a controller 19. The coloring nozzle 31 includes an electromagnetic valve 51. The signal generator 53 outputs signals for spouting the coloring material from the coloring nozzle 31 to both a CPU 62 of the controller 19 and a driving circuit 64. The CPU 62 outputs a signal for keeping the electromagnetic valve 51 open to the driving circuit 64 when a frequency of the signals from the signal generator 53 is higher than a specific frequency. When at least one of the signals from the CPU 62 and the signal generator 53 is inputted, the driving circuit 64 applies a spike voltage A and then applies a hold voltage B to a coil 40. While at least one of the signals from the CPU 62 and the signal generator 53 is inputted, the driving circuit 64 applies a spike voltage A and then continuously applies a hold voltage B to a coil 40.

Abstract: The switch device includes a control switch that turns on/off an electrical connection between an apparatus and the power supply, a condition judging circuit that judges conditions of driving the control switch, an electric wave reception circuit that receives an electric wave, and a power supply circuit that generates power from the electric wave received by the electric wave reception circuit. An electric wave transmission device that transmits an electric wave for making the switch device operate is arranged in a space, whereby the electric wave can be received by the electric wave reception device in the specific space. The switch device controls the control switch to be turned off/on when the electric wave is received. Alternatively, when the electric wave is not received, the switch device turns on/off the control switch.

Abstract: Relay circuitry for a power-over-network device is provided. The relay circuitry allows power-supplying network devices to identify and subsequently to supply power across a network connection to the power-over-network device, thereby eliminating the need for external power sources. The relay circuitry is operative using only the signals transmitted along a data line across the network connection. The relay circuitry is integrated together with switching circuitry on-chip on the power-over-network device. The relay circuitry and switching circuitry are further designed to propagate both the test signals and the subsequent data signals prior to and after the turning on of the power-over-network device, respectively, with minimal signal degradation.

Abstract: A system and method for detecting islanding in a Distributed Generation utility grid is described. In some examples, the system, via an inverter, injects a frequency disturbance to a location of the utility grid associated with a DG generator, measures both the frequency error due to the disturbance and the frequency drift of the location of the utility grid, and determines islanding based on a maximum value of the frequencies. In some cases, the system is able to reduce or minimize the Non-Detection Zone of the inverter by detecting islanding without always relying on a detectable frequency error due to an injected waveform.

Abstract: A target-closing phase-map generating section generates in advance a target closing phase map in consideration of a pre-arc characteristic and variations of a mechanical action of a breaker, and amplitude fluctuations of the load voltage. A target-closing time calculating section calculates a target closing time string from frequencies and phases of the power source voltage and the load voltage, respectively, of the breaker referring to the target closing phase map. A closing control section, when a close command 11 is inputted, controls the timing of outputting a closing control signal based on a predicted closing time and the target closing time string.

Abstract: A multi-output power supply device includes a first power switch, a first switch controller that controls the first power switch, a transformer that transforms a power supplied from the first power switch, first through Nth output circuits connected to a secondary side of the transformer, where N is a positive integer greater than 1, a second power switch that switches the power output from one of the first through Nth output circuits, a second switch controller that controls the second power switch, a feedback circuit that feeds back output voltages of the first through Nth output circuits, and a feedback compensation circuit that performs a switching operation complementarily with the second power switch to compensate for a resistance of the feedback circuit. Accordingly, when power output to one of the output circuits is blocked, the multi-output power supply device can stably control the power output to the other output circuits.

Abstract: A method and apparatus for providing isolated high and low direct current power supplies to a Power Device using a sealed high Power Device Gate Driver having a single transformer, wherein the Gate Driver integrates the power supplies, gating control and gate control, gate drive and Power Device diagnostics into a sealed unit, wherein the unit may be further sealed hermetically.

Abstract: A switching system. The switching system includes an optical component, an electromagnetic switch, an auxiliary adjustment structure, and a control circuit. The optical component reflects or refracts a light. The electromagnetic switch, on one side of the optical component, controls the optical component to rotate or move in a direction. The auxiliary adjustment structure, on the optical component, controls the optical component to rotate or move in other direction. The control circuit, coupled to the electromagnetic switch, adjusts an on-off signal of the electromagnetic switch by a native frequency of the switching system, wherein the native frequency is obtained from an initial signal.

Abstract: A fuel cell power management system and an anti-islanding method using the power management system. The power management system includes a fuel cell to generate direct current (DC) power, a power conditioning system (PCS) to generate alternating current (AC) power from the DC power generated by the fuel cell, a power grid that is connected to the PCS, a detector to detect a change in the AC power flowing from an output line of the PCS, and a controller to control the connection between the PCS and the power grid, according to the result of the detection.

Abstract: The invention relates to a method for determining the chance of a disturbance-free operation of a frequency converter (2) connected to a feeding network (18). According to the invention, during the operation of said frequency converter (2), an intermediate circuit voltage (UZK) is continuously measured and a network-side intermediate circuit current (iZKmains) is continuously determined; these measuring quantities are compared with pre-determined operating values of the frequency converter (2), and quantities which are higher or lower than said values are respectively stored; and the frequency (Hij) of said higher and lower measuring quantities is determined and converted into a characteristic number for the quality of the feeding network (18). As said characteristic number decreases, the chance of a disturbance-free operation of the frequency converter (2) increases.

Abstract: A control circuit and methods for controlling gas valves via a relay are provided. In one illustrative embodiment, a control circuit includes or is connected to a relay that controls the opening and/or closing of a gas valve. The control circuit may also include a failsafe circuit that has at least one input that can be connected to a control device and at least one output that can be connected to the relay. In some cases, the fail-safe circuit may only supply an output voltage and/or current to the replay for opening the gas valve if the input signal received from the control device includes at least two different successively applied frequency signals. Other methods and embodiments are also contemplated.